On two separate days I have spent some time taking pictures of the
Hudsonian Godwit currently at Hammo. Despite two or three hours observing the
bird, I discovered something in my pictures that I never noticed. The bird
has a Very Flexible upper mandible! When the bird opens its bill the upper
tip bends quite sharply upward/outward. I didn't know this was true of any
bird, but It is quite obvious in the pictures. The bend is apparently
created when the bird opens its bill, and I assume the same muscles perform
both functions.
At first I was mystified as to why a bird that jams its bill up to the
hilt into the ground (see pictures) would have or want a flexible bill, as I
assumed the more rigid the better for that function. After considering it
however, I have come up with what I believe may be the answer. If I'm wrong
I'm sure there are people who can give us the correct reason.
The bird rams its closed bill into the ground. If it encounters something
it wants to eat, how does it get the food (earthworm?) into the closed
bill? If you had 2 six inch sticks hinged at one end and sharp at the other
and pushed them into the ground, you would not be able to pry the 2 pieces
apart. I believe the bird is able to open Just The Tip of the bill enough
to grasp or suck in the food.
The Godwit appears to feed in a manner very similar to the way Ibis do,
but Ibis have big, heavy, and obviously very rigid bills. The mechanics of
how the two feed must be very different.
Pics at the link below:
http://www.photoshop.com/user/mntncougar/?galleryid=eb87888a8c924962af0d1776
36bd7d21&trackingid=BTAGC&wf=share
or
http://preview.tinyurl.com/yhdqxjc
Don Morgan
Coventry